The Hired Courier

Mosses don’t have pollen. They reproduce by releasing sperm cells that must swim through a film of water to reach the egg — a legacy of their aquatic ancestry. The range of this transport is millimeters. Fertilization requires proximity and moisture. In dry conditions or across distances, moss sperm cannot travel. The standard model: mosses are limited by water availability and physical adjacency.

Collembola — springtails, the tiny hexapods ubiquitous in soil — carry moss sperm on their bodies. So do oribatid mites. The animals walk through moss canopies, pick up sperm cells, and deposit them on distant female structures. The distances are orders of magnitude greater than sperm can swim. The transport is not incidental — the frequency and pattern suggest a functional reproductive strategy, analogous to insect pollination in flowering plants.

The parallel is striking. Flowering plants evolved flowers — colored, scented, nectar-producing structures — to attract insect pollinators. Mosses have none of this. They offer no reward, produce no signal, build no specialized structure. Yet the transport happens. The arthropods are not attracted to reproduction. They are attracted to the moss habitat itself — moisture, shelter, food — and the sperm transfer is a side effect of living there.

This flips the pollination analogy. Insect pollination is a mutual transaction: nectar for transport. Moss zoophily is exploitation without compensation — the moss benefits, the arthropod is indifferent. The courier doesn’t know it’s carrying a package. The package doesn’t know it has a courier. The system works because the courier lives where the package needs to go.

Mosses solved their distance problem 400 million years before flowers invented theirs.